GM LS3 Rectangle Port Carburettor Single Plane EFI Intake Manifold Black

Overview

Transform your GM LS3 rectangle port engine with this Street Single Plane EFI Intake Manifold in a sleek black finish. Designed to pair with 4-barrel square-bore carburettor setups, it delivers steady, even air and fuel distribution for enhanced street and strip performance. The low-rise, single-plane configuration keeps air velocity high to optimize throttle response and mid-range torque.

Fits and Compatibility

• Specifically for GM LS3 rectangle port engines running EFI.
• Intended for GM LS Gen III/IV engines equipped with rectangle port cylinder heads.
• Not compatible with factory OEM fuel rails; requires Aeroflow Fuel Rail Kit AF6999-6000 (included).
• Requires aftermarket injectors: either 14mm short (33.60mm) or 3/4" length (48.65mm) injectors (sold separately).

Carburettor and EFI Details

Carburettor mounting pad is 4150 square-bore (4-barrel) with a 4-bore carburettor pad. The design supports aftermarket 4150 square-bore throttle bodies or adapter plates for turbocharged applications, enabling a retro-fit look with a modern EFI setup.

Key Specifications

• Manifold type: Single Plane, EFI, low rise
• Carburettor pad: Square bore 4150 flange
• Overall height (carb pad to bottom): 122mm (check bonnet clearance)
• Port size: 1.15" x 2.50"
• RPM operating range: 2500 to 7000
• Gasket O-Ring: Included with manifold
• Carb studs: 5/16-18" x4
• Port plug: 3/8" NPT
• Mounting holes: 6 x 5/16-18"

What’s Included with the Manifold

• 8 x Intake Manifold O-Ring Gaskets (AF6233-5002)
• 4 x M6 x 1.00mm Hex Screws (80mm UHL)
• 6 x M6 x 1.00mm Hex Screws (50mm UHL)
• 10 x M6 Flat Washers
• 1 x 3/8" NPT Steel Port Plug

Fuel Rail Kit Details

• Includes Aeroflow Fuel Rail Kit AF6999-6000
• 2 x Fuel Rails (-8ORB)
• 1 x -8AN crossover braided line with two 90-degree non-full-flow fittings
• 3 x -8AN to -8ORB fittings
• 1 x -8ORB hex port plug
• 6 x long mounting brackets
• 6 x short mounting brackets
• 6 x 5/16-18" hex screws (18.5mm UHL)
• 6 x 5/16-18" hex screws (12mm UHL)
• 4 x M6 nuts
• 8 x 14mm Fuel Injector O-Rings

Application and Use Cases

Ideal for retro-fit street and performance builds that aim to run a 4150-style throttle body on GM LS engines while maintaining EFI control. The manifold’s design supports turbo-ready layouts via adapter plates and is crafted to suit LS3 rectangle port cylinder heads, delivering reliable airflow and fuel distribution across the RPM range.